# Python 2.6.4
# Project Euler, Problem 71
# Copyright 2010 Talha Zaman

m, mi = 0, 0;
pm, pmi = 0, 0;
for i in range(2,1000001):
    if i%7==0: continue
    test = int(i*3/7.)/float(i)
    if test > m:
        m = test
        mi = i
print int(mi*3/7.), "/", mi
